Method of preparing alumina catalyst, alumina catalyst prepared using same, and method of preparing propylene using alumina catalyst

Abstract

A method of preparing an alumina catalyst including: performing primary calcination of an alumina precursor at a primary calcination temperature to form a mixed-phase alumina including 1% to 15% by weight of alpha-alumina, 60% to 95% by weight of theta-alumina, and 4% to 25% by weight of delta-alumina; steam-treating the mixed-phase alumina with water vapor at a steam-treating temperature lower than the primary calcination temperature to form activated mixed-phase alumina; and performing secondary calcination of the activated mixed-phase alumina at a secondary calcination temperature higher than the steam treatment temperature and lower than the primary calcination temperature after step S2. An alumina catalyst prepared using the method, and a method of preparing propylene using the alumina catalyst.

The invention claimed is: 
     
       1. A method of preparing an alumina catalyst comprising the steps of:
 performing primary calcination of an alumina precursor at a primary calcination temperature to form a mixed-phase alumina comprising 1% to 15% by weight of alpha-alumina, 60% to 95% by weight of theta-alumina, and 4% to 25% by weight of delta-alumina; 
 steam-treating the mixed-phase alumina with water vapor at a steam-treating temperature lower than the primary calcination temperature to form activated mixed-phase alumina, wherein the steam-treating temperature is 200° C. to 500° C.; and 
 performing secondary calcination of the activated mixed-phase alumina at a temperature higher than the steam-treating temperature and lower than the primary calcination temperature, wherein the secondary calcination temperature is of greater than 500° C. and less than or equal to 600° C. 
 
     
     
       2. The method according to  claim 1 , wherein the primary calcination temperature is 900° C. to 1,100° C. 
     
     
       3. The method according to  claim 1 , wherein the primary calcination is performed for 8 hours to 12 hours. 
     
     
       4. The method according to  claim 1 , wherein the steam-treating is performed for 1 hour to 10 hours. 
     
     
       5. The method according to  claim 1 , wherein the secondary calcination is performed for 3 hours to 7 hours. 
     
     
       6. The method according to  claim 1 , wherein the mixed-phase alumina does not comprise gamma-alumina. 
     
     
       7. The method according to  claim 1 , wherein the alumina precursor comprises one or more selected from gibbsite, bayerite, boehmite, and diaspore. 
     
     
       8. The method according to  claim 1 , wherein the alumina catalyst is a catalyst for isopropyl alcohol dehydration. 
     
     
       9. An alumina catalyst prepared by the method according to  claim 1 . 
     
     
       10. A method of preparing propylene comprising a step of dehydrating isopropyl alcohol using the alumina catalyst according to  claim 9 .